No O.D. A4LD

[Maniak]

A few weeks ago, I thought the OD stopped working.. After watching the rpms at freeway etc.. I figured out that it was the Lockup that wasn't working...

I could tell since when I got up to 55-70mph at light throttle and then pushed a little harder on the throttle the rpms woudl go up.. If Lockup is working, pressing a little more on the throttle will make the rpms go up as speed goes up.. If the rpms go up without the speed the lockup isn't working.

So, you can check if it is lockup or OD by doing the following 2 tests (at least for a '92)..

Put the truck in drive (not od) get up to 50mph and cruise there. Now that your cruising, push a little harder on the throttle.. If lockup is working the rpms go up as the speed does...
Now put the gear selector into OD.. If OD is working it should shift one more time.. and you can again double check if lockup is working by pressing on the throttle a little.

This will at least let you know which thing you are chasing...

now on our X, it was the lockup that wasn't working.. I backprobed the wire that goes down to the trany and hooked it to a volt meter (yes I had a wire running from under the hood into the open drivers window ). When the computer told the tranny to go to lockup the voltage went from 13v down to .5 volts. That told me the computer was saying "lockup" but the tranny wasn't. I then backprobed down by the tranny and found that there was no voltage there.

In my case, the wire that went from the harness up top (in engine compartment) was broken (melted) before it got to the tranny. I fixed the wire and all is fine...

Your fix may not be so easy, but at least you will know which is your problem and if it is electrical or not... (sounds like it is in your case)

~Mark

 

[Glacier991]

Mr. Short is, as usual, correct and I was incorrect. So that leavesus with possibly on the electrical side: a) no TCC lockup, and/or; b) No 3/4 shift solenoid function and no lockup; or, c) no 3/4 shift solenoid function.

TCC lockup is likely electrical from what I know (cringing). 3/4 could be either electrical or a plugged screen (the "it worked after I changed the fluid" is suggestive of this). On the other hand the fact that the VSS driven aspects of the vehicle alternately worked and didn't work simaltaneously tends to point at an electrical problem. If it is both TCC and 3/4 the common link seems more probably eletrical.

I'd think the electrical may be the easiest to tackle first.

ps. Thank you Mr. Shorty for being so kind.... the words "dumb ass" come to mind as I reread that post of mine and engage the use of my brain.

pps. good post Maniac

 

[slag]

My 91 had a no tc lockup/ partial-sometimes-if-the-weather-was-right tc lockup situation. I swapped the TPS (no code given for it, but idle would vary between 1400 and 700 rpm "sometimes")

Problem solved.

The TC gets an incorrect reading from the TPS. Basically, the TPS says the throttle is not open so the torque converter thinks it should not be engaged.

 

[Mike_H]

Summer of 2002 my OD went out. I had all sorts of things done to it and none of it worked. Finally I hade it rebuilt and it has not skipped a beat yet.

 

[Dignan]

Mine skips a beat every day.

 

[Brandons]

I have the exact same problem, will check soon!